From arizona tonight, we are hearing for the first time those last moments of the granite mountain hot shots, those 19 first responders who died fighting a fierce wild fire in arizona. Their last radio transmissions captured by a helmet cam, just now being released. And here tonight, abc's aditi roy. Reporter: You can hear the panic in their voices when they come face to face with the inferno. Breaking in on arizona 16, granite mountain hot shots, we are in front of the flaming front. Reporter: That fire in the distance, recorded on the helmet cam of a nearby firefighting team. This is the last time the 19 granite mountain hot shots were in contact with their command center. The men don't know their tragic fate is just moments away. Air attack, granite mountain seven, how do you copy me? I hear saws running. That's not good. Reporter: The chain saws may have been used as a last desperate measure for the team, to cut down trees and debris, providing fuel for the flames. Then, the final transmission from the hot shots. Yeah, I'm here with granite mountain hot shots, our escape route has been cut off. We are preparing a deployment site and we are burning out around ourselves in the brush and I'll give you a call when we are under the shelters. Reporter: The hot shots had two minutes to deploy those shelters to take cover. The temperature, 2,000 degrees. Air command tries desperately to radio them, but are met with silence. Granite mountain seven, bravo 33 air to ground. Reporter: The silence, 19 lives lost in one of the worst wild fire disasters in history. Aditi roy, abc news, los angeles.

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